1. Field of the Invention
This invention relates, generally, to surgical tools. More particularly, it relates to an adaptor for cannulas used in laparoscopic surgery.
2. Description of the Prior Art
The size of an incision is minimized in laparoscopic surgery so that post-operative recovery is faster and less painful than conventional large incision surgery. A trocar is a tube-like tool that is inserted into a small incision; it can be left in position so that its lumen provides a passageway for other surgical tools that are used in the course of a surgical procedure. This avoids the trauma that would be associated with insertion and withdrawal of various instruments during the course of the surgery.
U.S. Pat. No. 5,957,902 to the present inventor provides an improved trocar. Before the invention of the improved trocar it was sometimes necessary to remove a relatively small diameter trocar from an incision and to insert a larger one. This defeats the purpose of a trocar which is to minimize multiple withdrawals and insertion of instruments through an incision. The invention disclosed in the referenced patents thus provides a trocar having a diameter that can be increased without requiring withdrawal of the trocar.
A trocar has utility, for example, where gas under pressure must be introduced into a patient's abdominal cavity. An elongate hose is employed to provide fluid communication between a remote gas machine and a cannula, and the cannula is introduced into the abdominal cavity through the lumen of the trocar. Adaptors for interconnecting the hose to a proximal end of the cannula are commercially available, but they are relatively expensive because they are made from multi-cavity molds. If the connection is not secure, the hose may separate from the proximal end of the cannula.
Accordingly, there is a need for an improved adaptor that is relatively inexpensive and easy to use. The improved adaptor should be substantially leak free and it should securely engage the cannula so that the cannula is not easily disconnected from the gas machine during surgery.
There is also a need for an adaptor having utility with conventional trocars as well.
However, in view of the art considered as a whole at the time the present invention was made, it was not obvious to those of ordinary skill in this art how the identified needs could be met.